webdriverexception:抛出一个带有空响应的异常，并停止selenium测试运行

我正在使用firefox浏览器驱动程序运行firefox 41.0.2Nunit 3.4.1硒2.47.0specflow魅惑我的测试是并行运行的

过了几天，我的测试一直未能完成，而运行jenkins，运行卡住了一个进程，不能继续运行的其余部分。在运行20多个场景时，我间歇性地能够在本地重现错误。我得到下面的例外，有人见过这个问题吗?

OpenQA.Selenium。WebDriverException:发送一个HTTP请求到远程WebDriver服务器的URL http://localhost:7056/hub/session/d0a83b9c-bd79-4218-8eac-dc8b273f8f40/element/%7B84966a91-06c4-42dd-98c0-278ed35e3667%7D/attribute/value时抛出了一个空响应的异常。

异常状态为ConnectFailure，消息为:Unable to connect to The remote server----> system.net.webeexception:无法连接到远程服务器----> System.Net.Sockets.SocketException: No connection could make，因为目标机器主动拒绝它127.0.0.1:7056

+++++++++++++++++++堆栈跟踪:在OpenQA.Selenium.Remote.HttpCommandExecutor。连接CreateResponse (WebRequest请求)在OpenQA.Selenium.Firefox.FirefoxDriverCommandExecutor。commandToExecute执行(命令)在OpenQA.Selenium.Remote.RemoteWebDriver。执行(String driverCommandToExecute, Dictionary 2 parameters) at OpenQA.Selenium.Remote.RemoteWebElement.GetAttribute(String attributeName) at TeamHours.Automation.StandAlone.WebComponents.Pages.WeeklySalesForecastPage.<Save>b__0(IWebElement s) in c:'Program Files (x86)'Jenkins'jobs'Automation Build Develop'workspace'TeamHours.Automation.StandAlone.WebComponents'Pages'WeeklySalesForecastPage.cs:line 38 at System.Linq.Enumerable.WhereSelectEnumerableIterator .)在System.Linq.Enumerable。任意[TSource](IEnumerable 1 source, Func 2 predicate)在TeamHours.Automation.StandAlone.WebComponents.Pages. weeklysalesforecastpage . save()中c:'Program Files (x86)'Jenkins'jobs'Automation构建开发'workspace'TeamHours.Automation.StandAlone.WebComponents'Pages'WeeklySalesForecastPage.cs:行39在c:'Program Files (x86)'Jenkins'jobs'Automation构建开发'workspace'TeamHours.Automation.StandAlone.CommonSteps'Steps'SalesForecast'WeeklySalesForecastGraphsSteps.cs:第73行在TechTalk.SpecFlow.Bindings.BindingInvoker。调用绑定，IContextManager contextManager，对象[]参数，ITestTracer testTracer, TimeSpan&持续时间)在TechTalk.SpecFlow.Infrastructure.TestExecutionEngine。ExecuteStepMatch(BindingMatch，对象[]参数)在TechTalk.SpecFlow.Infrastructure.TestExecutionEngine。ExecuteStep (StepInstance StepInstance)在TechTalk.SpecFlow.Infrastructure.TestExecutionEngine.OnAfterLastStep ()在c:'Program Files (x86)'Jenkins'jobs'Automation构建开发'workspace' teamhours . automation . standalone . regressiontests 'Features'Schedule' schedulegraph .Features. cs:第0行在TeamHours.Automation.StandAlone.RegresionTests.Features.Schedule.ScheduleGraphFeature。VerifyScheduleGraphShowsCorrectPeopleAndOverstaffedWhenDemandIsExceeded(字符串角色，字符串标签，字符串链接，字符串noOfItems，字符串peoplerrequired，字符串itemsOrSales，字符串tab2，字符串视图，字符串总数，字符串tab3，字符串type1，字符串type2，字符串type3，字符串[]exampleTags)在c:'Program Files (x86)'Jenkins'jobs'Automation构建开发'workspace' teamhour.automa.standalone.regressiontests 'Features'Schedule'ScheduleGraph。特点:133行——WebException在System.Net.HttpWebRequest.GetResponse ()在OpenQA.Selenium.Remote.HttpCommandExecutor。连接CreateResponse (WebRequest请求)——SocketException在System.Net.Sockets.Socket。DoConnect(EndPoint endPointSnapshot, SocketAddress, SocketAddress)在System.Net.ServicePoint。ConnectSocketInternal(Boolean connectFailure, Socket s4, Socket s6, Socket&套接字,IPAddress&地址，ConnectSocketState状态，IAsyncResult asyncResult，异常&例外)